The Dresden Codex, one of only four Maya books to survive the Spanish conquest, devotes one of its most carefully worked sections to a table tracking the planet Venus through its full 584-day cycle of morning-star and evening-star appearances and periods of invisibility, corrected across multiple cycles with real astronomical precision.
This was not simply a matter of intellectual curiosity. Maya inscriptions and painted ceramics record specific historical military campaigns explicitly timed to Venus's heliacal rising as morning star, glyphs modern epigraphers read as "star war" events, when a particular king's attack on a rival center is dated to coincide with Venus's reappearance. Susan Milbrath's Star Gods of the Maya documents this pattern across the corpus: Venus in its morning-star aspect was read as an omen of conquest, and warfare was scheduled to fall under its influence deliberately, the way a modern general might choose a date for symbolic reasons, except that the date itself was believed to carry real supernatural weight for the outcome.
Quetzalcoatl, in his aspect as Tlahuizcalpantecuhtli, is this same morning star among the Aztec, inheriting a Venus identification shared across Mesoamerican cultures generally rather than confined to the Maya, and his own myth of descent into the underworld and difficult return echoes the planet's own disappearance and reemergence. The connection between a documented astronomical table, a documented military practice, and a major deity's own name and myth is one of the clearest cases anywhere in the world of a society building both practical calculation and religious meaning around the same observed celestial cycle.